Since 2003 work has been under way on a four billion euro system to protect historic Venice from the ravages of floods. At its heart is an innovative barrier, which Rolls-Royce is helping to put in place at one of the three inlets where the Venice lagoon meets the Adriatic Sea: Lido, Malamocco and Chioggia.
The idea – to place barriers across the inlets which can be raised at high tides or severe storms. For the majority of the time, the barriers will be filled with water and remain flat on the seabed, attached to concrete caissons. But at times of risk, estimated to be three to five times a year, the barriers will be pumped full of air, enabling them to rise on hinges, to block the tidal flow.
The caissons, which will each support three gates each one connected by two hinges, both weighing 45 tonnes, are being built on temporary building sites. The larger caissons – for Malamocco and the Lido channel – are all being built at Malamocco, where work on the casting plant is well under way.
That process of transferring them to the sea involves a Rolls-Royce Syncrolift® system and a rail-mounted transfer system. As one might expect, moving these giant structures by rail is not a quick business – they will move at a metre a minute to the launch area. Here, the caissons will be transferred into the water by a Syncrolift® platform supported by 26 hoists of 1,200 tonnes capacity each. The platform itself weighs 4,000 tonnes.
A Syncrolift® is usually used for the docking and transfer of ships, and the product is a world market leader with more than 230 systems designed in 69 countries, but the principle is also well suited to caisson build and launch and has been successfully applied on several Far East and Gulf projects.
The Syncrolift® concept comprises four key elements – a structural steel platform, electro-mechanical hoists, wire ropes and a control system.
Diagram of how the Syncrolift® will work in Venice